These signs and symptoms may occur within a month after you've been infected:

Rash. A small, red bump may appear at the site of the tick bite. This small bump is normal after a tick bite and doesn't indicate Lyme disease. However, over the next few days, the redness may expand forming a rash in a bull's-eye pattern, with a red outer ring surrounding a clear area. The rash, called erythema migrans, is one of the hallmarks of Lyme disease. Some people develop this rash at more than one place on their bodies.

In some people, the rash may spread to other parts of the body and, several weeks to months after you've been infected, you may experience:

Joint pain. You may develop bouts of severe joint pain and swelling. Your knees are especially likely to be affected, but the pain can shift from one joint to another.

Neurological problems. Weeks, months or even years after you were infected, you may experience inflammation of the membranes surrounding your brain (meningitis), temporary paralysis of one side of your face (Bell's palsy), numbness or weakness in your limbs, and impaired muscle movement.

Less common signs and symptoms

Several weeks after infection, some people develop:

Heart problems, such as an irregular heartbeat. Heart problems rarely last more than a few days or weeks.

Eye inflammation.

Liver inflammation (hepatitis).

Severe fatigue.

When to see a doctor

If you've been bitten by a tick and experience symptoms

Only a minority of deer tick bites leads to Lyme disease. The longer the tick remains attached to your skin, the greater your risk of getting the disease. If you think you've been bitten and experience signs and symptoms of Lyme disease — particularly if you live in an area where Lyme disease is prevalent — contact your doctor immediately. Treatment for Lyme disease is most effective if begun early.

See your doctor even if symptoms disappear

It's important to consult your doctor even if signs and symptoms disappear because the absence of symptoms doesn't mean the disease is gone. Left untreated, Lyme disease can spread to other parts of your body from several months to years after infection — causing arthritis and nervous system problems. Ticks also can transmit other illnesses, such as babesiosis and Colorado tick fever.